Which one of the following failure theories is the most conservative design approach against fatigue failure?

A solid massless cylindrical member of 50 mm diameter is rigidly attached at one end, and is subjected to an axial force $P = 100$ kN and a torque $T = 600$ N.m at the other end as shown. Assume that the axis of the cylinder is normal to the support.

Considering distortion energy theory with allowable yield stress as $300$ MPa, the factor of safety in the design is _____ (rounded off to 1 decimal place).

A band brake shown in the figure has a coefficient of friction of 0.3. The band can take a maximum force of 1.5 kN. The maximum braking force (F) that can be safely applied is _______ N (rounded off to the nearest integer).

The "Earing" phenomenon in metal forming is associated with